Battery management system

Abstract

A battery management system includes a plurality of balancing resistors that are respectively connected to a plurality of cells that are connected in series to each other, and that respectively form a part of a balancing discharge path of each of the cells, a plurality of balancing switches configured to respectively control a flow of balancing current of the balancing discharge path, a voltage detection circuit configured to detect a voltage of opposite ends of a respective balancing resistor with respect to a balancing target cell among the cells when cell balancing is started, and a balancing control circuit configured to acquire a voltage cumulative value corresponding to a cumulative value of balancing discharge current of the balancing target cell using the voltage of the opposite ends of the respective balancing resistor, and configured to determine whether cell balancing on the balancing target cell is terminated based on the voltage cumulative value.

What is claimed is: 
     
       1. A battery management system comprising:
 a plurality of balancing resistors that are respectively connected to a plurality of cells that are connected in series to each other, and that respectively form a part of a balancing discharge path of each of the cells; 
 a plurality of balancing switches configured to respectively control a flow of balancing current of the balancing discharge path; 
 a voltage detection circuit configured to detect a voltage of opposite ends of a respective balancing resistor with respect to a balancing target cell among the cells when cell balancing is started; and 
 a balancing control circuit configured to acquire a voltage cumulative value corresponding to a cumulative value of balancing discharge current of the balancing target cell using the voltage of the opposite ends of the respective balancing resistor, and configured to determine whether cell balancing on the balancing target cell is terminated based on the voltage cumulative value, 
 wherein the voltage detection circuit is respectively connected to the opposite ends of the respective balancing resistor to detect the voltage of the opposite ends of the respective balancing resistor. 
 
     
     
       2. The battery management system of  claim 1 , wherein the balancing switches, the voltage detection circuit, and the balancing control circuit are in a battery integrated circuit (IC). 
     
     
       3. The battery management system of  claim 2 , wherein the battery IC further comprises a plurality of balancing terminals respectively connected to first electrodes of the cells,
 wherein the balancing resistors are respectively connected between the first electrodes and the balancing terminals, and 
 wherein the balancing switches are each between a respective pair of neighboring balancing terminals among the balancing terminals. 
 
     
     
       4. The battery management system of  claim 3 , wherein the battery IC further comprises a plurality of input terminals respectively connected to the first electrodes,
 wherein the voltage detection circuit comprises:
 an analog-to-digital converter configured to convert voltages input through first and second inputs thereof into digital data, and configured to output the digital data; 
 a plurality of first switches configured to respectively switch connection between the input terminals and the first input of the analog-to-digital converter; and 
 a plurality of second switches configured to respectively switch connection between the balancing terminals and the second input of the analog-to-digital converter, and 
 
 wherein, when cell balancing is started, respective ones of the first and second switches are controlled to connect the opposite ends of the respective balancing resistor to the balancing target cell. 
 
     
     
       5. A battery management system comprising:
 a plurality of balancing resistors that are respectively connected to a plurality of cells that are connected in series to each other, and that respectively form a part of a balancing discharge path of each of the cells; and 
 a battery integrated circuit (IC) comprising:
 a plurality of balancing terminals respectively connected to first electrodes of the cells; 
 a plurality of input terminals respectively connected to the first electrodes; 
 a plurality of balancing switches configured to respectively control a flow of balancing current of the balancing discharge path, each of the balancing switches being between a respective pair of neighboring ones of the balancing terminals; 
 a voltage detection circuit configured to detect a voltage of opposite ends of a respective balancing resistor with respect to a balancing target cell among the cells when cell balancing is started, the voltage detection circuit comprising:
 an analog-to-digital converter configured to convert voltages input through a first input and a second input thereof into digital data, and configured to output the digital data; 
 a plurality of first switches configured to respectively switch connection between the input terminals and the first input of the analog-to-digital converter; and 
 a plurality of second switches configured to respectively switch connection between the balancing terminals and the second input of the analog-to-digital converter; and 
 
 a balancing control circuit configured to acquire a voltage cumulative value corresponding to a cumulative value of balancing discharge current of the balancing target cell using the voltage of the opposite ends of the respective balancing resistor, and configured to determine whether cell balancing on the balancing target cell is terminated based on the voltage cumulative value, the balancing control circuit comprising:
 an integrator configured to acquire the voltage cumulative value from the digital data when cell balancing is started; 
 a comparator configured to output a result obtained by comparing the voltage cumulative value and a target voltage cumulative value that corresponds to the balancing target cell; and 
 a balancing switch control logic configured to control the balancing switch corresponding to the balancing target cell in response to an output of the comparator, 
 
 
 wherein the balancing resistors are respectively connected between the first electrodes and the balancing terminals, 
 wherein, when cell balancing is started, respective ones of the first and second switches are controlled to connect opposite ends of the respective balancing resistor to the balancing target cell, and 
 wherein the digital data corresponds to the voltage of the opposite ends of the respective balancing resistor. 
 
     
     
       6. The battery management system of  claim 5 , further comprising a battery controller configured to calculate a balancing factor of each of the cells from cell state information of each of the cells, and configured to calculate the target voltage cumulative value from the balancing factor. 
     
     
       7. The battery management system of  claim 3 , wherein the battery IC further comprises a plurality of input terminals respectively connected to the first electrodes,
 wherein the voltage detection circuit comprises:
 an analog-to-digital converter configured to convert voltages input through a first input and a second input thereof into digital data, and configured to output the digital data; 
 a plurality of first switches configured to respectively switch connection between the input terminals and the first input of the analog-to-digital converter; and 
 a plurality of second switches configured to respectively switch connection between the input terminals and the second input of the analog-to-digital converter, and 
 
 wherein the first and second switches are controlled to sequentially connect the first electrodes and second electrodes of each of the cells to the first and second inputs of the analog-to-digital converter during cell voltage detection with respect to the cells. 
 
     
     
       8. The battery management system of  claim 7 , further comprising a plurality of filter resistors respectively connected between the first electrode of the cells and the input terminals. 
     
     
       9. The battery management system of  claim 7 , wherein the battery IC further comprises a cell voltage register configured to store the digital data as a cell voltage of each of the cells during cell voltage detection on the cells. 
     
     
       10. The battery management system of  claim 7 , wherein the voltage detection circuit further comprises:
 a plurality of third switches configured to respectively switch connection between the balancing terminals and the first input of the analog-to-digital converter; and 
 a plurality of fourth switches configured to respectively switch connection between the balancing terminals and the second input of the analog-to-digital converter, and 
 wherein the third switches and the fourth switches are controlled to sequentially connect the first and second electrodes of each of the cells to the first and second inputs of the analog-to-digital converter, instead of the first and second switches, during cell voltage detection on the cells. 
 
     
     
       11. A battery management system comprising:
 a plurality of balancing resistors that are respectively connected to a plurality of cells that are connected in series to each other, and that respectively form a part of a balancing discharge path of each of the cells, the cells comprising a plurality of odd numbered cells, and a plurality of even numbered cells; and 
 a battery integrated circuit (IC) comprising:
 a plurality of balancing switches configured to respectively control a flow of balancing current of the balancing discharge path; 
 a voltage detection circuit configured to detect a voltage of opposite ends of a respective balancing resistor with respect to a balancing target cell among the cells when cell balancing is started; 
 a balancing control circuit configured to acquire a voltage cumulative value corresponding to a cumulative value of balancing discharge current of the balancing target cell using the voltage of the opposite ends of the respective balancing resistor, and configured to determine whether cell balancing on the balancing target cell is terminated based on the voltage cumulative value; 
 a plurality of first balancing terminals connected to first electrodes of the odd numbered cells, respectively; 
 a plurality of second balancing terminals connected to second electrodes of the even numbered cell, respectively; and 
 a plurality of common terminals connected to second electrodes of the odd numbered cells, respectively, 
 
 wherein the balancing resistors comprise a plurality of first balancing resistors that are respectively connected between the first electrodes of the odd numbered cells and a plurality of first balancing terminals, and a plurality of second balancing resistors that are respectively connected between the second electrodes of the even numbered cells and a plurality of second balancing terminals, and 
 wherein the balancing switch comprises a plurality of first balancing switches that are respectively connected between the first balancing terminals and the common terminals, and a plurality of second balancing switches that are respectively connected between the second balancing terminals and the common terminals. 
 
     
     
       12. The battery management system of  claim 11 , wherein the battery IC further comprises a plurality of first input terminals respectively connected to the first electrodes of the odd numbered cells, and a plurality of second input terminals respectively connected to the second electrodes of the even numbered cells,
 wherein the voltage detection circuit comprises:
 an analog-to-digital converter configured to convert voltages input through a first input and a second input thereof into digital data, and to output the digital data; 
 a plurality of first switches configured to respectively switch connections between the first input terminals and the first input of the analog-to-digital converter; 
 a plurality of second switches configured to respectively switch connections between the input terminals and the second input of the analog-to-digital converter; 
 a plurality of third switches configured to respectively switch connections between the first balancing terminals and the second input of the analog-to-digital converter; and 
 a plurality of fourth switches configured to respectively switch connections between the second balancing terminals and the first input of the analog-to-digital converter, 
 
 wherein the first switches and the third switches are controlled to connect the opposite ends of the first balancing resistors to the first and second inputs of the analog-to-digital converter when cell balancing is started, and 
 wherein the second switches and the fourth switches are controlled to connect the opposite ends of the second balancing resistors to the first and second inputs of the analog-to-digital converter when cell balancing is started. 
 
     
     
       13. The battery management system of  claim 12 , wherein the balancing control circuit comprises:
 an integrator configured to acquire the voltage cumulative value from the digital data when cell balancing is started; 
 a comparator configured to output a result obtained by comparing the voltage cumulative value, and a target voltage cumulative value corresponding to the balancing target cell; and 
 a balancing switch control logic configured to control the balancing switch corresponding to the balancing target cell in response to an output of the comparator, and 
 wherein a voltage value output from the analog-to-digital converter during cell balancing corresponds to the voltage of the opposite ends of the respective balancing resistors. 
 
     
     
       14. The battery management system of  claim 13 , further comprising a battery controller configured to calculate a balancing factor of each of the cells from cell state information of each of the cells, and to calculate the target voltage cumulative value from the balancing factor. 
     
     
       15. The battery management system of  claim 11 , wherein the battery IC further comprises a plurality of input terminals respectively connected to the first electrodes of the cells,
 wherein the voltage detection circuit comprises:
 an analog-to-digital converter configured to convert voltages input through a first input and a second input thereof into digital data, and to output the digital data; 
 a plurality of first switches configured to respectively switch connections between the input terminals and the first input of the analog-to-digital converter; and 
 a plurality of second switches configured to respectively switch connections between the input terminals and the second input of the analog-to-digital converter, and 
 
 wherein the first switches and the second switches are controlled to sequentially connect the first and second electrodes of the cells to the first and second inputs of the analog-to-digital converter during cell voltage detection with respect to the cells. 
 
     
     
       16. The battery management system of  claim 15 , further comprising a plurality of filter resistors respectively connected between the first electrodes of the cells and the input terminals.